The analytical potential of combined capillary electrophoresis/electrospray ionization mass spectrometry (CE/ESI MS) and combined capillary zone electrophoresis/electrospray ionization tandem mass spectrometry (CE/ESI MS-MS) will be developed for application to high sensitivity primary sequence determination of peptides. Methods for "pico-scale" sample handling, isolation, enzymatic digestion and injection to the several modes of capillary electrophoresis will be developed. These methods will be particularly adapted to the efficient utilization of sub-picomolar peptide and protein samples provided by excised portions of two dimensional gel electrophoresis preparations or electroblot membranes. Enzymatic digests will be separated by capillary free zone electrophoresis, electrophoresis in gel filled capillaries, capillary isotachophoresis or capillary isoelectric focusing with dynamic detection Dy electrospray ionization mass spectrometry. The phenomena of multiple charging of proteins and peptides observed in electrospray ionization will be exploited to extend the practical molecular weight range accessible by mass spectrometry and to enhance the collision induced dissociation (MS-MS) sequencing of peptides. Instrumentation and methodology developed will permit the rapid sub-picomolar sequence analysis of peptides, as the constituents of mixtures which will complement high sensitivity automated sequence determination in the sub-picomolar range. This will enhance of the rapidity and accuracy of specific gene mapping studies and other investigations where derived information from proteins and peptides is of critical importance.